A door mirror assembly for a vehicle has been conventionally constructed of various elements and sub-assemblies, including a mirror, a control sub-assembly for controlling the angle of mirror and a drive sub-assembly for positioning the door mirror assembly in a retracted or an operative position, which are installed in a shell called door mirror housing. Since a door mirror housing, which is made of a synthetic resin, is susceptible to mechanical deformation such as torsion, it has been common to incorporate an element such as a frame into the door mirror housing. In this case, the door mirror housing and frame are commonly fixed with fasteners such as screws at three locations or more. Japanese Patent No. 3301571 (Japanese Published Patent application 07-223489) and Japanese Published Patent Application 10-100794 disclose the related techniques.
In this connection, other two documents report techniques, which do not employ screws for fixing a door mirror housing and a frame. Japanese Published Patent Application 2001-294087 discloses clips made of a synthetic resin or Japanese Published Patent Application 08-244532 discloses the application of ultrasonic welding.
It is understood that a reduction in the number of parts and man-hour expenditure will contribute to a reduction in the production cost of a door mirror assembly for a vehicle. It is therefore important to improve working efficiency as a result of a reduction in the number of fasteners such as screws in fixing a door mirror housing and a frame. However, if the number of fasteners such as screws and clips is decreased carelessly for a conventional door mirror assembly, the resultant fixation strength will be inadequate. It leads to posing a problem that chattering of a mirror during vehicular travel adversely affects the visibility of a driver or noise spoils the comfortableness in a cabin.